The third Interim Report, Part , describes the testing and selection of metallic and non-metallic materials for application in pressure-testing apparatus to determine the life term of HAN-based liquid propellants (LPs). Metallic materials are necessary for pressure sensors and non-metallic materials for sealing of the testing apparatus. Selection criteria for the metals are their corrosion-resisting quality and their capacity to influence or restrict the chemical stability of the LP. Selection criteria for the sealing materials are their impermeability to gases, deformation under strain and compatibility with the LP used. The testing apparatus is being used at the present time. Testing results will be discussed in the next Interim Report. The 2nd Part of the present Report will describe the experiments carried out on the long-term storage of LP 1846 in glass ampoules at 90 C (194 F). Keywords: Liquid propellants, Monergols, Long term stability, Decomposition time, Life term.